Clipboard test snippet to get/set text data in JRuby and SWT.

clipboard.rb

require 'java'
require 'swt'

module Swt
  include_package 'org.eclipse.swt'
  include_package 'org.eclipse.swt.widgets'
  include_package 'org.eclipse.swt.dnd'
  import java.awt.datatransfer.StringSelection
  import java.awt.Toolkit
end

class Object
  include Swt
end

display = Swt::Display.new
shell = Swt::Shell.new display
shell.setSize 300+16, 300+38
cs = Swt::Composite.new shell, Swt::SWT::NONE
cs.setSize 300, 300

cb_get = Swt::Clipboard.new display
cb_set = Swt::Toolkit.getDefaultToolkit.getSystemClipboard
tt = Swt::TextTransfer.getInstance

b = Swt::Button.new cs, Swt::SWT::NULL
b.setText 'get'
b.setLocation 50, 50
b.pack
b.addSelectionListener do
  p cb_get.getContents(tt) # Works well!
end

b = Swt::Button.new cs, Swt::SWT::NULL
b.setText 'set'
b.setLocation 200, 50
b.pack
b.addSelectionListener do
  # cb.setContents(['hello hello hello'], tt) # NameError... why?
  cb_set.setContents Swt::StringSelection.new('hello hello hello'), self # Works well! Thanks, Roger!!
end

shell.open

while !shell.isDisposed do
  display.sleep unless display.readAndDispatch
end
display.dispose

Getting the text data from the system clipboard works well at line 28.
But setting doesn't at line 36. Umm,....

Got a solution! Thanks to Roger!